What is the primary organ affected at the Ying Level?

The primary organ affected at the Ying Level is indeed the Heart. In Traditional Chinese Medicine (TCM), the Ying level is associated with the deeper aspects of pathogenic influence, particularly in cases of febrile disease. This level reflects a condition where the heat penetrates to the Ying (nutritive) Qi, leading to symptoms that can affect the Heart specifically, such as high fever, irritability, and insomnia.

The Heart holds a central position in TCM theory, regarded not just as an organ that pumps blood but as the "Emperor" of the internal organs, responsible for housing the mind and consciousness (Shen). When there is a disturbance at the Ying level, it often manifests as a direct impact on the Heart and its functions. This connection is reinforced by observations of pulse and diagnostic patterns consistent with heat that can disturb the Heart’s function at this level.

The other options pertain to different functions and associations in TCM and may relate to different levels or types of pathology but do not have the same direct connection to the Ying level as the Heart does. The Spleen is more associated with the transformation and transportation of nutrients, while the Liver is tied to the regulation of Qi flow and emotional aspects. The Lungs pert